Table 2: Physicochemical properties and relative capacities of nonspecific binding to the cell membrane for CdSe/ZnS QD570 encapsulated with mixtures of PEG-based polymers with different charges.
| QD surface functionalities | PL emission peak (nm) | ζ potential (mV) | Relative nonspecific binding of QDs to cell membrane |
|---|---|---|---|
| 100%PEG-OH | 568 | -6 | 10% |
| 95%PEG-OH + 5%PEG-NH2 | 568 | 6 | 20% |
| 80%PEG-OH + 20%PEG-NH2 | 570 | 17.5 | 40% |
| 60%PEG-OH + 40%PEG-NH2 | 571 | 36.7 | 60% |
| 100%PEG-NH2 | 573 | 43 | 100% |
| 100%PEG-COOH | 566 | -36 | 100% |
| 60%PEG-COOH + 40%PEG-OH | 567 | -28.1 | 60% |
| 40%PEG-COOH + 60%PEG-OH | 568 | -20.4 | 35% |
| 10%PEG-COOH + 90%PEG-OH | 569 | -15 | 30% |